They’re separate holidays, but July Fourth might as well be the same as Flag Day.

Flags blanket the District on July Fourth, flying from rooftops, cars and the waving hands of children atop their parents’ shoulders. At the heart of the city, two large flags fly from the top of the Capitol.

But behind the scenes, more than 800 flags are raised and lowered on the Capitol’s roof on July Fourth. There are three poles on the roof specifically for the purpose, and the Capitol flag office adds staff especially for the day. Last year, 865 flags flew on the holiday.

Constituents from across the country submit requests to their Members of Congress to fly flags over the Capitol.

They can request a flag flown on any date except Christmas, Thanksgiving and New Year’s Day. Memorial Day, Veterans Day and July Fourth generally see the largest numbers of requests, according to Architect of the Capitol spokeswoman Eva Malecki.

The program for flying flags began in 1937, when an unknown Member of Congress first requested a flag to be flown over the Capitol. His request was honored, and more requests were soon honored for flags to commemorate holidays and recognize school groups and civic organizations. Requests for flags eventually outnumbered the available supply, and the Architect of the Capitol began flying smaller flags on smaller poles for the requests.

Now, the large flags flown on the East Front and West Front of the Capitol fly for months at a time.

“We replace these flags on an as-needed basis — typically every few months,” Malecki said in an email. “But weather conditions can impact the wear and tear on the flags — rain, snow, and wind, especially. In those instances, the flags may be replaced more frequently.”

About 100,000 flags are flown each year over the Capitol for constituents — and 24,000 fly in the month of July. The number of requests varies greatly between offices; some offices receive more than 500 requests in a year, while others have received as few as two requests in a year.